Take the mystery out of what to give your plants, and instead put the microbes to work at the "root" of the issue. The microbial balance of bacteria, fungi, protozoa and nematodes cycle nutrients to the plant roots.
Testing is helpful at three stages: 1) To make sure compost itself has biology that is ready to serve your plant; 2) to see what is already present in your soil, and 3) after the compost solids or liquids have been applied to soil to determine if treatment increased the population to the numbers necessary for your crop. Note: This includes instruction on how to prepare your area to ensure proper moisture maintenance and oxygen for keeping the microbes in place.
Cost: $80-150 (depending on sample collection details). Pack of 3 $200-400 for use at any stage within 3 months of each other.